38 
SOME INSECTS INJURIOUS TO TRUCK CROPS. 
Time of reaching maturity. — After the adult has emerged from 
the pupal state between 12 and 24 hours are required for coloring 
and, perhaps, as much longer for it to work its way out of the soil. 
Beetles which appeared to be not over 4 days old were found in 
copula and, judging from these very unsatisfactory data, about 6 
days would be required for the beetles to become fully mature. 
Copulation. — Copulation was observed at all times of the day and 
even at night. Morning seems to be preferred, for more pairs were 
observed between 8 and 12 o'clock than in the afternoon. Although 
some remained together but a short time, others required three- 
fourths of an hour, and one pair which was closely watched took 50 
minutes for the operation. As long as there Avere beetles in the 
field pairs were to be found, and Mr. Hulbert states that he has 
observed them in copula up to the time that they went into hiberna- 
tion in the fall. 
O imposition. — When ready to oviposit, the female works her way 
down into the soil until she reaches the moist layer, where she lays 
her quota of eggs. Although this operation of egg-laying was not 
observed, the fact that the eggs were deposited through cheese cloth 
and even light cotton cloth leads the writer to believe that the long 
ovipositor (fig. 11) is worked into the firm soil before oviposition. 
The eggs would thus be concealed to some extent from predaceous 
enemies. 
Number of eggs and rate of egg-laying. — Beetles captured in 
copula and confined in vials laid from 4 to 18 eggs. Three pairs 
copulated again after ovipositing, but only one female laid eggs 
after this second copulation. Table I illustrates the number and rate 
of egg-laying as indicated by beetles kept under laboratory condi- 
tions : 
Table I. — Number of eggs and rate of egg-laying of the hop flea-beetle. 
Adult 
No. 
Dates of copulation. 
Dates first eggs 
were laid. 
Number 
first eggs 
laid. 
Dates second 
eggs were laid. 
Number 
second 
eggs laid. 
Death. 
1 
1909. 
April 22 and May 2 
1909. 
13 
6 
2 
11 
11 
1 
14 
9 
18 
10 
4 
1909. 
May 3 
5 
1909. 
(o) 
May 20. 
2 
May 10 
3 
June 9 
10 
June 19. 
4 
5 
...do 
...do... 
6 
do... 
7 
June 19. 
7 
do 
do 
June 15. 
8 
do 
June 10 
June 16. 
9 
...do... 
...do 
June 15. 
10 
...do... 
June 12 

June 16. 
11 
...do ... 
do... 
1 
) 
a Lost. 
Length of life of the beetle. — The length of life of the hop flea- 
beetle is quite variable. Several lots of newly emerged insects which 
